The study involved comparisons of groups of court- adjudicated, inner-city, multi-ethnic adolescent male subsamples. Boys who grew up in two-parent families (either with both biological parents or with one biological parent and a step- parent) (n=152) were compared with boys who grew up living with only their mother, and with relatively little contact with a father figure (n=153). Boys who grew up with both of their biological parents (n=94) were compared with boys who grew up living with only their mother, and with relatively little contact with a father figure (n=153). The analyses controlled for differences on 25 family-history variables and on the son's relationship with his mother and with his father. Subjects were drawn from a population of 350 adolescent male clients referred by the Family Court of Philadelphia. The findings provided no support for the hypothesis that the absence of the father is a risk factor for the son's becoming involved to a greater degree in either illegal behavior, drug trafficking, or substance use/abuse. The findings were consistent across four of the five analyses. The sons in one-parent, mother-only families tended to report less illegal and criminal behavior. Suggestions for future research are offered. 7 tables and 14 references